Lte/1x dual-standby with single-chip radio

ABSTRACT

Electronic devices may be provided that contain wireless communication circuitry. The wireless communication circuitry may include radio-frequency transceiver circuitry coupled to antennas by switching circuitry. Multiple radio access technologies may be supported. A device may include first and second antennas. Control circuitry can configure the transceiver circuitry and switching circuitry to support operation of the device in active and idle modes for each radio access technology. In some configurations, both antennas may be used to support operations associated with one of the radio access technologies. In other configurations, the first antenna may be used to support operations with a first of the radio access technologies while the second antenna is used to support operations with a second of the radio access technologies.

This application claims the benefit of provisional patent applicationNo. 61/476,736, filed Apr. 18, 2011, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

This relates generally to wireless communication circuitry, and moreparticularly, to electronic devices that have wireless communicationcircuitry that supports multiple radio access technologies.

Electronic devices such as portable computers and cellular telephonesare often provided with wireless communication capabilities. Forexample, electronic devices may use long-range wireless communicationcircuitry such as cellular telephone circuitry and WiMax (IEEE 802.16)circuitry. Electronic devices may also use short-range wirelesscommunication circuitry such as WiFi® (IEEE 802.11) circuitry andBluetooth® circuitry.

In some devices, it may be desirable to support multiple radio accesstechnologies. For example, it may be desirable to support newerradio-access technologies for handling data sessions and olderradio-access technologies for supporting voice calls. Examples ofdifferent radio-access technologies that have been used in cellulartelephones include Global System for Mobile Communications (GSM),Universal Mobile Telecommunications System (UMTS), Code DivisionMultiple Access (CDMA) (e.g., CDMA2000 including standards such asCDMA2000 1XRTT), and Long Term Evolution (LTE).

In theory, an electronic device may support any number of desired radioaccess technologies by incorporating sufficient hardware resources intothe device. For example, a device may operate an independent wirelesscircuit and a dedicated antenna for each radio access technology. Inpractice, however, such a scheme may be impractical. Besides theinefficiency of including a different radio chipset and antenna for eachsupported radio-access technology, this approach may not guaranteeimmunity from interference among the various radio access technologies.

It would therefore be desirable to be able to provide improved ways inwhich to support multiple radio access technologies in an electronicdevice.

SUMMARY

Electronic devices may be provided that contain wireless communicationcircuitry. The wireless communication circuitry may includeradio-frequency transceiver circuitry coupled to antennas usingswitching circuitry. Control circuitry may be used to adjust theconfiguration of the radio-frequency transceiver circuitry and theswitching circuitry.

The wireless communication circuitry may support operations usingmultiple radio access technologies. The antennas may include first andsecond antennas. The control circuitry can provide the transceivercircuitry and switching circuitry with dynamic control signals thatconfigure the electronic device to support various combinations ofactive and idle mode operation. For example, the transceiver circuitryand switching circuitry may be configured to allow both the first andsecond antennas to be simultaneously used to support operations for aparticular radio access technology or may be configured to allow thefirst antenna to be used in supporting a first radio access technologywhile the second antenna is used in supporting the second radio accesstechnology.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative electronic device withwireless communication circuitry in accordance with an embodiment of thepresent invention.

FIG. 2 is a schematic diagram of a wireless network including a basestation and an illustrative electronic device with wirelesscommunication circuitry in accordance with an embodiment of the presentinvention.

FIG. 3 is a diagram of illustrative wireless circuitry that may be usedin an electronic device in accordance with an embodiment of the presentinvention.

FIG. 4 is a diagram showing various modes of operation that may be usedin a wireless electronic device in accordance with an embodiment of thepresent invention.

FIG. 5 is a circuit diagram showing illustrative circuitry that may beused in implementing a wireless electronic device in accordance with anembodiment of the present invention.

FIG. 6 is a table showing illustrative possible modes of operation foran electronic device with multiple antennas that supports operationswith multiple radio access technologies in accordance with an embodimentof the present invention.

FIG. 7 is a timing diagram showing how an electronic device may supportoperation in an idle mode for a first radio access technology using oneantenna while supporting operation in an idle mode for a second radioaccess technology using another antenna in accordance with an embodimentof the present invention.

FIG. 8 is a timing diagram showing how an electronic device may supportan active data session using a first radio access technology whileperiodically using one of the antennas in the device to monitor a pagingchannel associated with a second radio access technology in accordancewith an embodiment of the present invention.

FIG. 9 is a timing diagram showing how an electronic device may monitora paging channel associated with a first radio access technology whileperiodically being adjusted to use multiple antennas to monitor a pagingchannel associated with a second radio access technology in accordancewith an embodiment of the present invention.

FIG. 10 is a timing diagram showing how an electronic device may operatean active mode for a first radio access technology while periodicallybeing interrupted to support use of multiple antennas to monitor apaging channel associated with a second radio access technology inaccordance with an embodiment of the present invention.

FIG. 11 is a timing diagram showing how an electronic device maytransition from an active mode associated with a first radio accesstechnology that uses multiple antennas to an active mode associated witha second radio access technology that uses a single antenna inaccordance with an embodiment of the present invention.

FIG. 12 is a timing diagram showing how an electronic device maytransition from an active mode associated with a first radio accesstechnology to an active mode associated with a second radio accesstechnology that uses two antennas in accordance with an embodiment ofthe present invention.

DETAILED DESCRIPTION

Electronic devices may be provided with wireless communicationcircuitry. The wireless communication circuitry may be used to supportmultiple radio access technologies (communications protocols). Forexample, an electronic device may support communications with a GlobalSystem for Mobile Communications (GSM) radio access technology, aUniversal Mobile Telecommunications System (UMTS) radio accesstechnology, a Code Division Multiple Access (CDMA) radio accesstechnology (e.g., CDMA2000 1XRTT or other CDMA radio accesstechnologies), a Long Term Evolution (LTE) radio access technology,and/or other radio access technologies.

In some embodiments, an electronic device may be described that supportsat least two radio access technologies such as LTE and CDMA2000 1XRTT(sometimes referred to herein as “1X”). Other radio access technologiesmay be supported if desired. The use of a device that supports two radioaccess technologies such as LTE and 1X radio access technologies ismerely illustrative.

The two (or more) radio access technologies for the electronic devicemay be supported using shared wireless communication circuitry such asshared radio-frequency transceiver circuitry and a common basebandprocessor integrated circuit (sometimes referred to as a “radio”).

The electronic device may have multiple antennas. For example, theelectronic device may have a pair of cellular telephone antennas. Theantennas may be coupled to the shared wireless communication circuitryusing switching circuits and other radio-frequency front-end circuitryin the wireless circuitry of the electronic device. The wirelesscircuitry can be configured in real time depending on the desired modeof operation for the device.

When configured to support normal LTE operations, each of the antennasin the device may be used in receiving a corresponding LTE data stream.The simultaneous use of two antennas to receive two LTE data streams (atype of arrangement that is sometimes referred to as receiver diversityor receive diversity) helps to improve received data rates. Accordingly,the use of receive diversity is specified by the LTE protocol.

To avoid missing incoming 1X calls, a 1X paging channel may be monitoredonce per 1X paging cycle. To ensure that disruption to an active LTEdata session is minimized, 1X page monitoring operations can beperformed by temporarily using one of the antennas for 1X pagemonitoring while the other of the antennas continues to be used forreceiving LTE data. In some situations, received signal strength in the1X paging channel is low. In these situations, both of the antennas canbe temporarily used in receiving 1X paging channel signals. After the 1Xpaging channel has been monitored for a desired time period (sometimesreferred to as a 1X wake period), the antennas can again both be usedfor LTE data.

This antenna allocation scheme may be performed continuously duringoperation of the electronic device. Both antennas may be used for LTEtraffic during periods of time in which the 1X paging channel does notneed to be monitored. When the time arrives for monitoring the 1X pagingchannel, one or both of the antennas being used to handle LTE trafficcan be temporarily used for monitoring the 1X paging channel.

An illustrative electronic device of the type that may be used tosupport multiple radio access technologies is shown in FIG. 1.Electronic device 10 may be a portable electronic device or othersuitable electronic device. For example, electronic device 10 may be alaptop computer, a tablet computer, a somewhat smaller device such as awrist-watch device, pendant device, headphone device, earpiece device,or other wearable or miniature device, a cellular telephone, a mediaplayer, etc.

Device 10 may include a housing such as housing 12. Housing 12, whichmay sometimes be referred to as a case, may be formed of plastic, glass,ceramics, fiber composites, metal (e.g., stainless steel, aluminum,etc.), other suitable materials, or a combination of these materials. Insome situations, parts of housing 12 may be formed from dielectric orother low-conductivity material. In other situations, housing 12 or atleast some of the structures that make up housing 12 may be formed frommetal elements.

Device 10 may, if desired, have a display such as display 14. Display 14may, for example, be a touch screen that incorporates capacitive touchelectrodes. Display 14 may include image pixels formed fromlight-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells,electronic ink elements, liquid crystal display (LCD) components, orother suitable image pixel structures. A cover glass layer may cover thesurface of display 14. Portions of display 14 such as peripheral regions20I may be inactive and may be devoid of image pixel structures.Portions of display 14 such as rectangular central portion 20A (boundedby dashed line 20) may correspond to the active part of display 14. Inactive display region 20A, an array of image pixels may be used todisplay images for a user.

The cover glass layer that covers display 14 may have openings such as acircular opening for button 16 and a speaker port opening such asspeaker port opening 18 (e.g., for an ear speaker for a user). Device 10may also have other openings (e.g., openings in display 14 and/orhousing 12 for accommodating volume buttons, ringer buttons, sleepbuttons, and other buttons, openings for an audio jack, data portconnectors, removable media slots, etc.).

Housing 12 may include a peripheral conductive member such as a bezel orband of metal that runs around the rectangular outline of display 14 anddevice 10 (as an example). The peripheral conductive member may be usedin forming the antennas of device 10 if desired.

Antennas may be located along the edges of device 10, on the rear orfront of device 10, as extending elements or attachable structures, orelsewhere in device 10. With one suitable arrangement, which issometimes described herein as an example, device 10 may be provided withone or more antennas at lower end 24 of housing 12 and one or moreantennas at upper end 22 of housing 12. Locating antennas at opposingends of device 10 (i.e., at the narrower end regions of display 14 anddevice 10 when device 10 has an elongated rectangular shape of the typeshown in FIG. 1) may allow these antennas to be formed at an appropriatedistance from ground structures that are associated with the conductiveportions of display 14 (e.g., the pixel array and driver circuits inactive region 20A of display 14).

If desired, a first cellular telephone antenna may be located in region24 and a second cellular telephone antenna may be located in region 22.Antenna structures for handling satellite navigation signals such asGlobal Positioning System signals or wireless local area network signalssuch as IEEE 802.11 (WiFi®) signals or Bluetooth® signals may also beprovided in regions 22 and/or 24 (either as separate additional antennasor as parts of the first and second cellular telephone antennas).Antenna structures may also be provided in regions 22 and/or 24 tohandle WiMax (IEEE 802.16) signals.

In regions 22 and 24, openings may be formed between conductive housingstructures and printed circuit boards and other conductive electricalcomponents that make up device 10. These openings may be filled withair, plastic, or other dielectrics. Conductive housing structures andother conductive structures may serve as a ground plane for the antennasin device 10. The openings in regions 22 and 24 may serve as slots inopen or closed slot antennas, may serve as a central dielectric regionthat is surrounded by a conductive path of materials in a loop antenna,may serve as a space that separates an antenna resonating element suchas a strip antenna resonating element or an inverted-F antennaresonating element such as an inverted-F antenna resonating elementformed from part of a conductive peripheral housing structure in device10 from the ground plane, or may otherwise serve as part of antennastructures formed in regions 22 and 24.

Antennas may be formed in regions 22 and 24 that are identical (i.e.,antennas may be formed in regions 22 and 24 that each cover the same setof cellular telephone bands or other communications bands of interest).Due to layout constraints or other design constraints, it may not bedesirable to use identical antennas. Rather, it may be desirable toimplement the antennas in regions 22 and 24 using different designs(e.g., using different antenna types and/or designs that exhibitdifferent gains). For example, the first antenna in region 24 may coverone set of cellular telephone bands of interest and the second antennain region 22 may cover a different set of cellular telephone bands ofinterest (as an example). Tuning circuitry may be used to tune anantenna in real time to cover either a first subset of bands, or asecond subset of bands, and thereby cover all bands of interest.

If desired, an antenna selection control algorithm that runs on thecircuitry of device 10 can be used to automatically select whichantenna(s) are used in device 10 in real time. The antennas may, forexample, contain a primary antenna (e.g., an antenna in region 24 thatexhibits a first gain) and a secondary antenna (e.g., an antenna inregion 24 that exhibits a second gain that is less than the first gain).The antenna selection control algorithm may configure circuitry indevice 10 so that the primary antenna is connected to a first portassociated with a baseband processor and so that the secondary antennais connected to a second port associated with the baseband processor orvice versa. Antenna selections may, for example, be based on theevaluated signal quality of received signals. In addition to selectingwhich antenna(s) are to be used in receiving signals, the circuitry ofdevice 10 may be used in adjusting the transceiver circuitry andbaseband processor circuitry of device 10. For example, the circuitry ofdevice 10 may be temporarily configured so that one or both of theantennas is used in monitoring a 1X paging channel for incoming 1Xpaging signals.

Device 10 may use any suitable number of antennas (e.g., two or moreantennas, three or more antennas, etc.), but configurations in which twoantennas are used are sometimes described herein as an example. Device10 may use antennas that are substantially identical (e.g., in bandcoverage, in efficiency, etc.), or may use other types of antennaconfigurations.

A schematic diagram of a system in which electronic device 10 mayoperate is shown in FIG. 2. As shown in FIG. 2, system 11 may includewireless network equipment such as base station 21. Base stations suchas base station 21 may be associated with a cellular telephone networkor other wireless networking equipment. Device 10 may communicate withbase station 21 over wireless link 23 (e.g., a cellular telephone linkor other wireless communication link).

Device 10 may include control circuitry such as storage and processingcircuitry 28. Storage and processing circuitry 28 may include storagesuch as hard disk drive storage, nonvolatile memory (e.g., flash memoryor other electrically-programmable-read-only memory configured to form asolid state drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in storage andprocessing circuitry 28 and other control circuits such as controlcircuits in wireless communication circuitry 34 may be used to controlthe operation of device 10. This processing circuitry may be based onone or more microprocessors, microcontrollers, digital signalprocessors, baseband processors, power management units, audio codecchips, application specific integrated circuits, etc.

Storage and processing circuitry 28 may be used to run software ondevice 10, such as internet browsing applications,voice-over-internet-protocol (VoIP) telephone call applications, emailapplications, media playback applications, operating system functions,etc. To support interactions with external equipment such as basestation 21, storage and processing circuitry 28 may be used inimplementing communications protocols. Communications protocols that maybe implemented using storage and processing circuitry 28 includeinternet protocols, wireless local area network protocols (e.g., IEEE802.11 protocols—sometimes referred to as WiFi®), protocols for othershort-range wireless communications links such as the Bluetooth®protocol, IEEE 802.16 (WiMax) protocols, cellular telephone protocolssuch as the Long Term Evolution (LTE) protocol, Global System for MobileCommunications (GSM) protocol, Code Division Multiple Access (CDMA)protocol, and Universal Mobile Telecommunications System (UMTS)protocol, etc.

Circuitry 28 may be configured to implement control algorithms fordevice 10. The control algorithm may be used to control radio-frequencyswitching circuitry, transceiver circuitry, and other device resources.For example, the control algorithm may be used to configure wirelesscircuitry 34 to switch a particular antenna into use for transmittingand/or receiving signals or may switch multiple antennas into usesimultaneously. The control algorithm may also be used to activate anddeactivate transmitters and receivers, to tune transmitters andreceivers to desired frequencies, to implement timers, to comparemeasured device operating parameters to predetermined criteria, etc.

In some scenarios, circuitry 28 may be used in gathering sensor signalsand signals that reflect the quality of received signals (e.g., receivedpilot signals, received paging signals, received voice call traffic,received control channel signals, received data traffic, etc.). Examplesof signal quality measurements that may be made in device 10 include biterror rate measurements, signal-to-noise ratio measurements,measurements on the amount of power associated with incoming wirelesssignals, channel quality measurements based on received signal strengthindicator (RSSI) information (RSSI measurements), channel qualitymeasurements based on received signal code power (RSCP) information(RSCP measurements), reference symbol received power (RSRPmeasurements), channel quality measurements based onsignal-to-interference ratio (SINR) and signal-to-noise ratio (SNR)information (SINR and SNR measurements), channel quality measurementsbased on signal quality data such as Ec/Io or Ec/No data (Ec/Io andEc/No measurements), etc. This information and other data may be used incontrolling how the wireless circuitry of device 10 is configured andmay be used in otherwise controlling and configuring device 10.

Input-output circuitry 30 may be used to allow data to be supplied todevice 10 and to allow data to be provided from device 10 to externaldevices. Input-output circuitry 30 may include input-output devices 32.Input-output devices 32 may include touch screens, buttons, joysticks,click wheels, scrolling wheels, touch pads, key pads, keyboards,microphones, speakers, tone generators, vibrators, cameras, sensors,light-emitting diodes and other status indicators, data ports, etc. Auser can control the operation of device 10 by supplying commandsthrough input-output devices 32 and may receive status information andother output from device 10 using the output resources of input-outputdevices 32.

Wireless communication circuitry 34 may include radio-frequency (RF)transceiver circuitry formed from one or more integrated circuits, poweramplifier circuitry, low-noise input amplifiers, passive RF components,one or more antennas, and other circuitry for handling RF wirelesssignals.

Wireless communication circuitry 34 may include satellite navigationsystem receiver circuitry such as Global Positioning System (GPS)receiver circuitry 35 (e.g., for receiving satellite navigation systemsignals at 1575 MHz). Transceiver circuitry 36 may handle associatedbands for WiFi® (IEEE 802.11) communications, for example, 2.4 GHz and 5GHz bands, and may handle the 2.4 GHz Bluetooth® communications band.Circuitry 34 may use cellular telephone transceiver circuitry 38 forhandling wireless communication in cellular telephone bands such asbands at 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz orother cellular telephone bands of interest. Wireless communicationcircuitry 34 can include circuitry for other short-range and long-rangewireless links if desired (e.g., WiMax circuitry, etc.). Wirelesscommunication circuitry 34 may, for example, include, wireless circuitryfor receiving radio and television signals, paging circuits, etc. InWiFi® and Bluetooth® links and other short-range wireless links,wireless signals are typically used to convey data over tens or hundredsof feet. In cellular telephone links and other long-range links,wireless signals are typically used to convey data over thousands offeet or miles.

Wireless communication circuitry 34 may include antennas 40. Antennas 40may be formed using any suitable types of antenna. For example, antennas40 may include antennas with resonating elements that are formed fromloop antenna structures, patch antenna structures, inverted-F antennastructures, closed and open slot antenna structures, planar inverted-Fantenna structures, helical antenna structures, strip antennas,monopoles, dipoles, hybrids of these designs, etc. Different types ofantennas may be used for different bands and combinations of bands. Forexample, one type of antenna may be used in forming a local wirelesslink antenna (e.g., for handling WiFi® traffic or other wireless localarea network traffic) and another type of antenna may be used in forminga remote wireless link antenna (e.g., for handling cellular networktraffic such as voice calls and data sessions). As described inconnection with FIG. 1, there may be multiple cellular telephoneantennas in device 10. For example, there may be one cellular telephoneantenna in region 24 of device 10 and another cellular telephone antennain region 22 of device 10. These antennas may be fixed or may betunable.

Device 10 can be controlled by control circuitry that is configured tostore and execute control code for implementing control algorithms. Asshown in FIG. 3, control circuitry 42 may include storage and processingcircuitry 28 (e.g., a microprocessor, memory circuits, etc.) and mayinclude baseband processor integrated circuit 58. Baseband processor 58may form part of wireless circuitry 34 and may include memory andprocessing circuits (i.e., baseband processor 58 may be considered toform part of the storage and processing circuitry of device 10).

Baseband processor 58 may provide data to storage and processingcircuitry 28 (e.g., a microprocessor, nonvolatile memory, volatilememory, other control circuits, etc.) via path 48. The data on path 48may include raw and processed data associated with wireless (antenna)performance metrics for received signals such as received power,transmitted power, frame error rate, bit error rate, channel qualitymeasurements based on received signal strength indicator (RSSI)information, channel quality measurements based on received signal codepower (RSCP) information, channel quality measurements based onreference symbol received power (RSRP) information, channel qualitymeasurements based on signal-to-interference ratio (SINR) andsignal-to-noise ratio (SNR) information, channel quality measurementsbased on signal quality data such as Ec/Io or Ec/No data, information onwhether responses (acknowledgements) are being received from a cellulartelephone tower corresponding to requests from the electronic device,information on whether a network access procedure has succeeded,information on how many re-transmissions are being requested over acellular link between the electronic device and a cellular tower,information on whether a loss of signaling message has been received,information on whether paging signals have been successfully received,and other information that is reflective of the performance of wirelesscircuitry 34. This information may be analyzed by storage and processingcircuitry 28 and/or processor 58 and, in response, storage andprocessing circuitry 28 (or, if desired, baseband processor 58) mayissue control commands for controlling wireless circuitry 34. Forexample, storage and processing circuitry 28 may issue control commandson path 52 and path 50 and/or baseband processor 58 may issue commandson path 46 and path 51.

Wireless circuitry 34 may include radio-frequency transceiver circuitrysuch as radio-frequency transceiver circuitry 60 and radio-frequencyfront-end circuitry 62. Radio-frequency transceiver circuitry 60 mayinclude one or more radio-frequency transceivers such as transceivers 57and 63. Some transceivers may include both a transmitter and a receiver.If desired, one or more transceivers may be provided with receivercircuitry, but no transmitter circuitry (e.g., to use in implementingreceive diversity schemes). As shown in the illustrative configurationof FIG. 3, transceiver 57 may include a transmitter such as transmitter59 and a receiver such as receiver 61 and transceiver 63 may include atransmitter such as transmitter 67 and a receiver such as receiver 65.

Baseband processor 58 may receive digital data that is to be transmittedfrom storage and processing circuitry 28 and may use path 46 andradio-frequency transceiver circuitry 60 to transmit correspondingradio-frequency signals. Radio-frequency front end 62 may be coupledbetween radio-frequency transceiver 60 and antennas 40 and may be usedto convey the radio-frequency signals that are produced byradio-frequency transceiver circuitry 60 to antennas 40. Radio-frequencyfront end 62 may include radio-frequency switches, impedance matchingcircuits, filters, and other circuitry for forming an interface betweenantennas 40 and radio-frequency transceiver 60.

Incoming radio-frequency signals that are received by antennas 40 may beprovided to baseband processor 58 via radio-frequency front end 62,paths such as paths 54 and 56, receiver circuitry in radio-frequencytransceiver 60, and paths such as path 46. Path 54 may, for example, beused in handling signals associated with transceiver 57, whereas path 56may be used in handling signals associated with transceiver 63. Basebandprocessor 58 may convert received signals into digital data that isprovided to storage and processing circuitry 28. Baseband processor 58may also extract information from received signals that is indicative ofsignal quality for the channel to which the transceiver is currentlytuned. For example, baseband processor and/or other circuitry in controlcircuitry 42 may analyze received signals to produce bit error ratemeasurements, measurements on the amount of power associated withincoming wireless signals, strength indicator (RSSI) information,received signal code power (RSCP) information, reference symbol receivedpower (RSRP) information, signal-to-interference ratio (SINR)information, signal-to-noise ratio (SNR) information, channel qualitymeasurements based on signal quality data such as Ec/Io or Ec/No data,etc.

Radio-frequency front end 62 may include switching circuitry. Theswitching circuitry may be configured by control signals received fromcontrol circuitry 42 (e.g., control signals from storage and processingcircuitry 28 via path 50 and/or control signals from baseband processor58 via path 51). The switching circuitry may include a switch (switchcircuit) that is used to connect transceiver 57 to antenna 40B andtransceiver 63 to antenna 40A or vice versa. Radio-frequency transceivercircuitry 60 may be configured by control signals received from storageand processing circuitry over path 52 and/or control signals receivedfrom baseband processor 58 over path 46.

The number of receivers and antennas that are used may depend on theoperating mode for device 10. For example, in normal LTE operations,antennas 40A and 40B may be used with respective receivers 61 and 65 toimplement a receive diversity scheme for device 10. With this type ofarrangement, two LTE data streams may be simultaneously received andprocessed using baseband processor 58. When it is desired to monitor a1X paging channel for incoming 1X pages, one or both of the antennas maybe temporarily used in receiving 1X paging channel signals.

Control circuitry 42 may be used to run software for handling more thanone radio access technology. For example, baseband processor 58 mayinclude memory and control circuitry for implementing multiple protocolstacks 590 such as protocol stack 1X and protocol stack LTE. Protocolstack 1X may be associated with a first radio access technology such asCDMA2000 1XRTT (as an example). Protocol stack LTE may be associatedwith a second radio access technology such as LTE (as an example).During operation, device 10 may use protocol stack 1X to handle 1Xfunctions and may use protocol stack LTE to handle LTE functions.Additional protocol stacks, additional transceivers, additional antennas40, and other additional hardware and/or software may be used in device10 if desired. The arrangement of FIG. 3 is merely illustrative.

It may be desirable to minimize the cost and complexity of device 10 byimplementing the wireless circuitry of FIG. 3 using an arrangement inwhich baseband processor 58 and radio-transceiver circuitry 60 can beused to support both LTE and 1X traffic.

The 1X radio access technology may generally be used to carry voicetraffic, whereas the LTE radio access technology may generally be usedto carry data traffic. To ensure that 1X voice calls are not interrupteddue to LTE data traffic, 1X operations may take priority over LTEoperations. To ensure that operations such as monitoring a 1X pagingchannel for incoming paging signals do not unnecessarily disrupt LTEoperations, control circuitry 42 can, whenever possible, configure thewireless circuitry of device 10 so that wireless resources are sharedbetween LTE and 1X functions.

When a user has an incoming 1X call, the 1X network may send device 10 apaging signal (sometimes referred to as a page) on the 1X paging channelusing base station 21. When device 10 detects an incoming page, device10 can take suitable actions (e.g., call establishment procedures) toset up and receive the incoming 1x call. Pages are typically sentseveral times at fixed intervals by the network, so that devices such asdevice 10 will have multiple opportunities to successfully receive apage.

Proper 1X page reception requires that the wireless circuitry of device10 be periodically tuned to the 1X paging channel. If the transceivercircuitry 60 fails to tune to the 1X paging channel or if the 1Xprotocol stack in baseband processor 58 fails to monitor the pagingchannel for incoming pages, 1X pages will be missed. On the other hand,excessive monitoring of the 1X paging channel may have an adverse impacton an active LTE data session.

To conserve power, it may be desirable for the 1X and LTE protocolstacks to support idle mode operations (sometimes referred to as sleepmode functionality). During 1X idle mode, 1X voice operations that canbe supported include decoding/monitoring the quick paging channel(Q-PCH) when this feature has been enabled by the network operator,decode/monitor the paging channel, re-registering the device (if thedevice moves out of its previous registration zone), initiating a systemscan when a device enters an out-of-service condition, and readingoverhead messages on the network control channel (e.g., messagesconveying information such as base station identifier information,network identifier information, information on which optional featureshave been enabled by the network operator, etc.).

Three potential operating states may be associated with idle modeoperation: wake mode, sleep mode, and out-of-service sleep mode.

When in wake mode, the device is monitored for pages from the networkand is monitored to determine whether device 10 is in service. If thedevice is not receiving a page and is in service, the device may beplaced in sleep mode. If the device is out of service, a system scan maybe performed to identify an available network. If no service isavailable, an out-of-service indicator may be displayed and the devicemay be placed in the out-of-service sleep mode for a period of time.Upon awakening from the out-of-service sleep mode, the device can onceagain search for service. If service is detected, the device may beplaced in sleep mode.

Periodically, the device should be awakened from sleep mode into wakemode. If the device receives a page during wake mode, a communicationlink may be established. For example, in a 1X network, call setupoperations may be performed to establish a 1X call (e.g., a voice call).Once the call is complete, the device may be returned to sleep mode.

This sleep-wake paging cycle may be repeated continuously duringoperation of device 10. Each paging cycle, the device may be awakenedfor a period of time to monitor the paging channel for incoming pages.To conserve power, the device is then returned to sleep mode unless anincoming page is detected.

Device 10 can support active and idle mode operations for both the 1Xand LTE radio access technologies. The ability of device 10 to supportboth 1X and LTE operations concurrently using wireless circuitry 34 andcontrol circuitry 42 depends on the 1X and LTE modes of operation.

Consider, as an example, the situation in which baseband processor 58and protocol stack 1X are being used to support 1X operations in idlemode while baseband processor 58 and protocol stack LTE are being usedto support LTE operations in either idle mode or active mode. If thesignal strength on the 1X paging channel is sufficient, one of theantennas in device 10 (e.g., antenna 40B or 40A of FIG. 3) may betemporarily used for 1X paging channel monitoring operations, ratherthan for LTE operations. Although this temporarily occupies one of thetwo antennas that are normally used to implement receive diversity forLTE operations, the remaining antenna in wireless circuitry 34 may stillbe used to handle LTE traffic. Environments where 1X paging signalstrength is sufficient to allow incoming pages to be received using onlya single 1X antenna therefore allow device 10 to operate in either LTEidle or active modes while simultaneously operating in 1x idle mode.

In environments in which device 10 is able to support active 1Xoperations using a single antenna (i.e., because 1X signal strengths aresufficiently strong), the remaining antenna may be used to support LTEidle mode operations.

FIG. 4 is a state diagram showing how device 10 may transition betweendifferent states during operation. During normal operations in which LTEtraffic is being conveyed between device 10 and network 23, device 10may use both antennas (e.g., antennas 40A and 40B of FIG. 3), asillustrated by state 100. The simultaneous use of two antennas allowsdevice 10 to implement a receive diversity scheme that is compliant withLTE protocols. During the operations of state 100, protocol stack LTEmay be used in receiving and processing two separate incoming streams ofLTE traffic. For example, receiver 61 and one of antennas 40 may be usedin receiving a first LTE traffic stream and receiver 65 and a second ofantennas 40 may be used in receiving a second LTE traffic stream.Baseband processor 58 may be provided with these two parallel LTE datastreams over path 46 and may combine the incoming traffic into data forcircuitry in device 10 such as storage and processing circuitry 28. Inconfigurations in which device 10 uses a single radio-frequencytransmitter (e.g., transmitter 59) for transmitting LTE data, circuitry42 may configure radio-frequency transceiver circuitry 60 andradio-frequency front-end circuitry 62 so that the transmitted signalsfrom transmitter 59 are routed to either antenna 40A or antenna 40B. LTEdual-antenna idle mode operations may also be performed in state 100.

To ensure that device 10 does not miss incoming 1X calls, device 10 mayperiodically transition to a state in which some or all LTEfunctionality is reduced and in which 1X page monitoring activities areperformed. Control circuitry 42 of device 10 may, for example,periodically transition device 10 to state 102 or state 104 of FIG. 4.

Control circuitry 42 may use signal quality measurements (e.g., receivedsignal strength indicators or other measurements of received signalquality) to determine whether to transition to state 102 or state 104.If signal quality is sufficient, device 10 may transition to state 102,where one antenna is used for LTE and one antenna is used for 1X (e.g.,1X active mode operations or 1X page monitoring activities). If signalquality is lower, the use of multiple antennas to handle 1X pagemonitoring activities may be desired, so device 10 may transition tostate 104, in which two antennas are used for 1X operations (e.g., inmonitoring the 1X paging channel for incoming pages).

Examples of signal quality measurements that may be made in device 10 todetermine whether include bit error rate measurements, signal-to-noiseratio measurements, measurements on the amount of power associated withincoming wireless signals, channel quality measurements based onreceived signal strength indicator (RSSI) information (RSSImeasurements), channel quality measurements based on received signalcode power (RSCP) information (RSCP measurements), reference symbolreceived power (RSRP measurements), channel quality measurements basedon signal-to-interference ratio (SINR) and signal-to-noise ratio (SNR)information (SINR and SNR measurements), channel quality measurementsbased on signal quality data such as Ec/Io or Ec/No data (Ec/Io andEc/No measurements), etc.

With one illustrative arrangement, device 10 will transition from state100 to state 102 to perform 1X page monitoring operations provided thatthe 1X signal quality has an RSSI value of greater than threshold TH1and will transition from state 100 to state 104 to perform 1X pagemonitoring operations when the 1X signal quality has an RSSI value ofless than TH1. Other signal quality measurements and thresholds may beused by control circuitry 42 to determine whether to transition to state102 or state 104. The use of RSSI signal quality measurements is merelyan example.

FIG. 5 is a circuit diagram showing illustrative circuitry that may beused in implementing device 10. In the illustrative example of FIG. 5,device 10 has two antennas—antenna 40A and 40B. If desired, device 10may have additional antennas 40, as described in connection with FIG. 3.Device 10 of FIG. 5 has radio-frequency transceiver circuitry 60 thatincludes two receivers (receiver circuitry 61 and receiver circuitry 65)and a transmitter (transmitter circuitry 59). Baseband processor 58 hasprotocol stacks 590 such as protocol stack LTE for handling LTEoperations and protocol stack 1X for handling 1X operations. Path 46 maybe used to couple baseband processor 58 to radio-frequency transceivercircuitry 60. Radio-frequency transceiver circuitry 60 may be coupled toantennas 40A and 40B via radio-frequency front end circuitry 62.

Data from baseband processor 58 may be conveyed to transmitter circuitry59 via path TX in path 46. Path 106 may be used to convey data that isto be transmitted to low-pass filter 108. Transmitter local oscillator112 may supply a local oscillator output signal to up-converter circuit110. Up-converter circuit 110 may upconvert the data signal fromlow-pass filter 108 and supply a corresponding radio-frequency outputsignal to amplifier 114. Amplifier 114 may amplify the radio-frequencysignal version of the transmitted data and provide this signal tomultiplexer circuit 116 (or other suitable switching circuitry).Multiplexer 116 may supply the data to path LTE TX when the transmitteddata is LTE data that is being provided by protocol stack LTE and maysupply the data to path 1X TX when the transmitted data is 1X data thatis being provided by protocol stack 1X. The state of multiplexer circuit116 and other circuits in transceiver 60 may be controlled by controlsignals supplied by baseband processor 58 and/or storage and processingcircuitry 28 (e.g., control circuitry 42 of FIG. 3).

Radio-frequency front-end circuitry 62 may include filter and switchingcircuitry for routing incoming and outgoing signals between transceivercircuitry 60 and antennas 40A and 40B. For example, radio-frequencyfront-end circuitry 62 may contain switching circuitry that implementsthe functions of a crossover (double-pole-double-throw) switch such asswitch 122. The state of switch 122 may be controlled by control signalsreceived on path C3 from control circuitry 42. In a first state, switch122 may route signals between port P10 and P11 and may route signalsbetween port P12 and P13. In a second (reversed) state, switch 122 mayconnect port P10 to port P13 and may connect port P12 to port P11.

The state of switch 122 may be used to control which receiver andtransmitter circuitry is coupled to each antenna. For example, the stateof switch 122 may be used to control whether transmitted signals aretransmitted through antenna 40A or antenna 40B. When it is in its firststate, transmitted signals such as LTE signals from path LTE TX or 1Xsignals from path 1X TX may be transmitted through antenna 40A. When itis in its second state, transmitted signals such as LTE signals frompath LTE TX or 1X signals from path 1X TX may be transmitted throughantenna 40B.

Transmitted LTE signals on path LTE TX may be amplified by amplifier128. Duplexer filter circuitry 118 may route signals based on theirfrequency. Incoming radio-frequency signals that are received from portP4 of switch 120 may be routed to path LTE RX1. Transmitted signals fromthe output of amplifier 128 may be routed to port P4 of switch 120.

Transmitted 1X signals on path 1X TX from multiplexer 116 may beamplified by amplifier 130. Duplexer filter circuitry 126 may routesignals based on their frequency. Radio-frequency signals that arereceived from port P5 of switch 120 may be routed to path 1X RX1.Transmitted signals from the output of amplifier 130 may be routed toport P5 of switch 120.

Radio-frequency switching circuitry in radio-frequency front-endcircuitry 62 such as radio-frequency switch 120 may be controlled bycontrol signals from control circuitry 42 that are received on controlsignal path C1. In a first state, radio-frequency switch 120 may coupleport P6 to port P4, in a second state, radio-frequency switch 120 maycouple port P6 to port P5. When ports P4 and P6 are connected, receivedradio-frequency signals from antenna structures 40 may be routed fromport P6 to port P4 and transmitted radio-frequency signals may be routedfrom port P4 to port P6 for transmission via antenna structures 40. Whenports P5 and P6 are connected, received radio-frequency signals fromantenna structures 40 may be routed from port P6 to port P5 andtransmitted radio-frequency signals may be routed from port P5 to portP6 for transmission via antenna structures 40.

Radio-frequency front-end circuitry 62 may also include radio-frequencyswitching circuitry such as radio-frequency switch 124. Radio-frequencyswitch 124 may be configured by control circuitry 42. In particular,radio-frequency switch 124 may receive control signals from controlcircuitry 42 on control signal input path C2. In response to the controlsignals received on path C2, radio-frequency switch 124 may be placed ina first state in which ports P7 and P9 are connected together or in asecond state in which a signal path is formed between ports P8 and P9.In its first state (i.e., when configuring switch 124 to receive LTEtraffic), received signals from crossover switch 122 may be routed fromport P9 to port P7 and associated signal path LTE RX2. In its secondstate (i.e., when configuring switch 124 to receive 1X traffic),received signals from crossover switch 122 may be routed from port P9 toport P8 and associated signal path 1X RX2.

Switching circuitry associated with radio-frequency transceivercircuitry 60 may be used in selectively routing signals from the fourreceive paths (LTE RX1, 1X RX1, LTE RX2, and 1X RX2) in radio-frequencyfront-end circuitry 62 to receiver circuits 61 and 65. Multiplexer 138may, for example, receive incoming radio-frequency signals on paths LTERX1 and 1X RX1 and may route signals from a selected one of these pathsto downconverter circuit 136 of receiver 61. Multiplexer 146 may receiveincoming radio-frequency signals on paths LTE RX2 and 1X RX2 and mayroute signals from a selected one of these paths to downconvertercircuit 148 of receiver 65.

Local oscillators RX LO may produce local oscillator output signals forreceivers 61 and 65. As shown in FIG. 5, for example, local oscillator140 may produce a radio-frequency output signal at frequency f2 that isreceived at port P1 of switching circuitry 144. Local oscillator 142 mayproduce radio-frequency output signals at frequency f1 that are providedto port P2 of switch 144 and to downconverter circuit 136 in receiver61. The state of switching circuitry 116, 138, 146, and 144 may becontrolled by control signals received from control circuitry 42 (e.g.,baseband processor 58 and/or storage and processing circuitry 28).

When it is desired to handle LTE signals with receiver 61, multiplexer138 may be used to route signals from path LTE RX1 to downconvertercircuitry 136. After mixing with the local oscillator output from localoscillator 142, the LTE signal from path LTE RX1 may be provided tobaseband processor 58 via low-pass filter 134, amplifier 132, and pathRX1. Baseband processor 58 may use protocol stack LTE to process thereceived LTE signals.

When it is desired to handle 1X signals with receiver 61, multiplexer138 may be used to route signals from path 1X RX1 to downconvertercircuitry 136. After mixing with the local oscillator output from localoscillator 142, the 1X signal from path 1X RX1 may be provided tobaseband processor 58 via low-pass filter 134, amplifier 132, and pathRX1. Baseband processor 58 may use protocol stack 1X to process thereceived 1X signals.

When it is desired to handle LTE signals with receiver 65, multiplexer146 may be used to route signals from path LTE RX2 to receiver 65. Whenit is desired to handle 1X signals with receiver 65, multiplexer 146 maybe used to route signals from path 1X RX2 to receiver 65.

The state of switch 144 may be used to determine whether downconvertercircuitry 148 is provided with the local oscillator output of localoscillator 140 at frequency f2 or the local oscillator output of localoscillator 142 at frequency f1. Switch 144 may be configured to coupleport P1 to port P3 when it is desired to provide downconverter 148 withthe output of local oscillator 140 at f2 and may be configured to coupleport P2 to port P3 when it is desired to provide downconverter 148 withthe output of local oscillator 142 at frequency f1. After mixing thereceived 1X or LTE signal from the output of multiplexer 146 with thelocal oscillator output from local oscillator 142 or the localoscillator output from local oscillator 140, downconverter circuitry 148may supply the received 1X or LTE signal to baseband processor 58 vialow-pass filter 150, amplifier 152, and path RX2 in path 46. Basebandprocessor 58 may use protocol stack LTE to process LTE signals from pathLTE RX2 and protocol stack 1X to process 1X signals from path 1X RX2.

In operating states in which it is desired to implement receivediversity, switch 144 may be configured to route the output of localoscillator 142 at frequency f1 to downconverter 148. Downconverter 136may simultaneously receive the output of local oscillator 142 atfrequency f1. In this configuration, receivers 61 and 65 may eachreceive incoming radio-frequency signals at the same frequency (i.e.,frequency f1) and may therefore be used in implementing a two-antennareceive diversity configuration for incoming LTE or 1X signals.

When signal strengths (e.g., a received signal strength indicator orother signal quality indicator information) indicate that a singleantenna may be used in receiving 1X paging signals, one of the antennas40A and 40B and one of receivers 61 and 65 may be used in receiving LTEsignals and the other of antennas 40A and 40B and the other of receivers61 and 65 may be used in receiving 1X signals. When using each receiverin radio-frequency transceiver circuitry 60 to handle a different typeof traffic, switch 144 may be configured to route the output of localoscillator 140 at frequency f2 to downconverter circuitry 148. Receiver61 may then be used to receive incoming signals at a first frequency(f1) while receiver 65 is used to simultaneously receive incomingsignals at a second frequency f2 that is different than the firstfrequency. Depending on the way in which circuitry 60 and circuitry 62is configured, LTE traffic may be handled by receiver 61 (i.e., LTEtraffic from path LTE RX1) while 1X traffic is handled by receiver 65(i.e., 1X traffic from path 1X RX2) or LTE traffic may be handled byreceiver 65 (i.e., LTE traffic from path LTE RX2) while 1X traffic ishandled by receiver 61 (i.e., 1X traffic from path 1X RX1).

FIG. 6 is a table illustrating how device 10 may operate under variouspossible combinations of 1X and LTE activity. Some potentialcombinations of 1X and LTE activities may be handled satisfactorilyusing circuitry of the type shown in FIG. 5, while others may lead toresource conflicts.

Consider, as an example, scenarios in which 1X functionality in device10 is idle (i.e., there is no active 1X voice call being handled bydevice 10 and device 10 is periodically monitoring the 1X paging channelfor incoming calls) and in which received 1X signal strength (asindicated by measured RSSI values or other signal quality factors) issufficient to allow device 10 to monitor the 1X paging channel usingonly a single one of the two antennas in device 10. These scenarios arerepresented by the first row of the table of FIG. 6. As shown in thefirst row of the table of FIG. 6, device performance may be satisfactorywhen device 10 is operating in an LTE idle state (monitoring forincoming LTE pages) and may be somewhat degraded when device 10 isoperating in an LTE active state.

FIG. 7 illustrates the type of wireless activity that may occur duringuse of device 10 to handle LTE idle and 1X idle operations (theleft-hand column of the first row of the table of FIG. 6). Because LTEand 1X functions are idle, there is no activity associated withtransmitter TX. During most periods of time, the switching circuitry inradio-frequency transceiver 60 and radio-frequency front-end circuitry62 may be configured to route incoming antenna signals to paths LTE RX1and LTE RX2. Switch 144 may be configured so that receiver 61 andreceiver 65 receive the signals on paths LTE RX1 and LTE RX2 using thesame local oscillator frequency (f1) (i.e., device 10 may be configuredto use both antennas in a receive diversity mode to monitor the LTEpaging channel at frequency f1 for incoming LTE pages). Periods of timein which LTE page monitoring is performed are indicated by the presenceof “LTE” page monitoring boxes for both the first receiver (RX1) andsecond receiver (RX2) in FIG. 7. First receiver RX1 may, for example,correspond to receiver 61 and second receiver RX2 may, for example,correspond to receiver 65 (or vice versa).

The 1X paging cycle may be longer than the LTE paging cycle. As aresult, device 10 may periodically need to use the second receiver RX2to monitor the 1X paging channel instead of the LTE paging channel. Tosupport this type of operation, the configuration of radio-frequencytransceiver circuitry 60 and radio-frequency front-end circuitry 62 maybe reconfigured by control circuitry 42. In particular, switch 144 maybe configured to couple port P1 to port P3, so that receiver 65 operatesat frequency f2 while receiver 61 operates at frequency f1. Switch 120may be configured to couple port P6 to port P4 to route received signalsfrom one of the antennas to path LTE RX1. Switch 124 may be configuredto couple port P9 to port P8 to route received signals from the other ofthe antennas to path 1X RX2. In the example of FIG. 5, switchingcircuitry is used to route signals. In configurations in which there areonly two radio-frequency bands involved, diplexer circuitry may be usedto route signals in device 10. The use of switching circuitry such asthe switching circuitry of FIG. 5 may be preferred when moreradio-frequency bands are involved.

As shown in FIG. 7, 1X pages and LTE pages can be simultaneouslymonitored by periodically using receiver RX2 to monitor the 1X pagingchannel for incoming pages rather than LTE signals. During these timeperiods (which are illustrated by the boxes labeled “1X” in FIG. 7), oneof the antennas in device 10 is used to provide signals to path 1X RX2while circuitry 60 monitors the signals on this path (at frequency f2)for incoming 1X pages. At the same time, LTE idle (page monitoring)operations can be performed using the remaining one of the antennas andcircuitry RX1. Although both antennas and receivers cannot besimultaneously used in monitoring LTE pages during the period in whichone of the antennas is being used to monitor 1X pages, this periodicmomentary loss of receive diversity for monitoring the LTE pagingchannel is generally acceptable. Performance is therefore satisfactory,as indicated in the left-hand column of the first row of the table ofFIG. 6.

As illustrated by the entry in the right-hand column of the first row ofthe table of FIG. 6, LTE performance may be degraded somewhat whenattempting to operate device 10 in an LTE active state whilesimultaneously monitoring the 1X channel for pages (i.e., operating thedevice in a 1X idle mode). FIG. 8 is a diagram showing how device 10 mayoperate in this situation. As shown in FIG. 8, transmitter TX may beused to transmit LTE data (e.g., using path LTE TX of FIG. 5 and anassociated one of antennas 40).

In the example of FIG. 8, LTE data is initially being received by device10 using a receive diversity arrangement. For example, at times such astime T1 of FIG. 8, before it is desired to monitor the 1X paging channelfor pages, LTE data may be received using both antennas and usingcorresponding receivers RX1 and RX2. When it is desired to monitor the1X channel for pages, normal LTE receive diversity operations may beinterrupted. In particular, LTE receive diversity operations may beperiodically interrupted (for the periods of time labeled “1X WAKE” inFIG. 8) to allow the antenna that is associated with receiver RX2 tomonitor the 1X paging channel for incoming 1X pages.

The transition between LTE receive diversity mode and the 1X pagemonitoring operations of periods “1X WAKE” in FIG. 8 may take place attimes such as time T2. Several transmission time intervals before timeT2 (and before each subsequent entry into the 1X WAKE state), device 10may send a rank indicator of 1 to the network (e.g., base station 21 ofFIG. 2). The rank indicator of 1 (or other suitable channel qualityindicator) directs the network to transmit data in a single layer only(i.e., in only one of the two simultaneous LTE data paths that arenormally transmitted during receive diversity operations). This helpsavoid data loss when one of the two LTE data paths becomes unavailableduring 1X paging channel monitoring. While the 1X paging channel isbeing monitored during period 1X WAKE, the remaining incoming LTE datastream can be handled by receiver RX1 and transmitter TX may be used fortransmitting LTE data. Following period 1X WAKE, 1X operations cease (goto sleep) and (during period 1X SLEEP), use of the antenna and receiverthat were temporarily used for 1X page monitoring may be returned to usein receiving one of the LTE data streams with device 10 sending acorresponding rank indicator to the LTE network (or other suitablechannel quality indicator).

With arrangements of the type described in connection with FIG. 8 (andthe right-hand side of the first row of the table of FIG. 6), there isno interruption in LTE service, but there is a degradation in receivedLTE data throughput due to the temporary loss of the second antenna andreceiver for receiving LTE data during periods 1X WAKE.

In some situations, received signal quality is poor, so it is notdesirable to attempt to receive 1X paging signals using only a singleantenna. When device 10 detects that this type of a situation hasarisen, 1X page monitoring activities (1X idle mode activities) may beperformed using both antennas (i.e., antennas 40A and 40B) andcorresponding receivers 61 and 65 in transceiver circuitry 60. Asindicated on the left-hand side of the second row of the table of FIG.6, 1X idle operations and LTE idle operations can be performedsimultaneously if their paging instances do not collide. As indicated onthe right-hand side of the second row of the table of FIG. 6, attemptsat performing 1X idle operations and LTE active mode operationssimultaneously will result in interrupted LTE operations.

During operations 1X idle mode and LTE idle mode, switch 120 may beconfigured to couple port P6 to port P5 to route received signals topath 1X RX1. Switch 124 may be configured to route received signals topath 1X RX2. Switch 144 may be configured to route the signals fromlocal oscillator 142 to port P3, so that signals on path RX2 and on pathRX1 correspond to the same frequency. The frequency may be adjusteddepending on whether device 10 is monitoring the LTE paging channel orthe 1X paging channel.

FIG. 9 is a diagram showing how device 10 may operate when performingsimultaneous 1X idle mode and LTE idle mode operations. LTE is in idlemode, so transmitter TX is not being used to transmit LTE data (in thisexample). During some time periods (labeled “LTE” in FIG. 9), the LTEpaging channel may be monitored for LTE pages. Both antennas andreceivers 61 and 65 may be used in performing these monitoringoperations (i.e., device 10 may be operated in an LTE receive diversitymode). Every 1X paging cycle, transceiver circuitry 60 may be tuned tothe 1X paging channel so that 1X pages can be monitored, as indicated bythe boxes in FIG. 9 that are labeled “1X”. Because device 10 hasdetected that signal quality is relatively low in this example (e.g.,because RSSI was measured to be less than a predetermined thresholdduring the wake period of a preceding paging cycle), device 10 (e.g.,control circuitry 42) configures wireless circuitry 34 so that 1X pagesare monitored using 1X receive diversity (i.e., using both antennas 40and using both receivers 61 and 65). The use of 1X receive diversityimproves signal reception, albeit at the expense of periodicallyresulting in a missed LTE paging cycle.

The diagram of FIG. 10, which corresponds to attempted simultaneous 1Xidle mode and LTE active mode operations (the right-hand side of thesecond row of the table of FIG. 6) shows how LTE operations areperiodically interrupted during periods PINT (i.e., when both antennasare used for monitoring 1X pages in a 1X receive diversity mode). Device10 may inform the network (base station 21 of FIG. 2) of each expectedLTE interruption by sending a rank indicator of 0 (or other suitablechannel quality indicator) to the network several transmission timeintervals (TTIs) before each 1X page monitoring period directing thenetwork to reduce data transmissions. In response, the network will stopor at least reduce data transmissions to device 10 during periods PINT,minimizing the impact of the LTE service interruptions during periodsPINT.

Device operation may be satisfactory in situations in which it isdesired to simultaneously perform 1X active mode operations with oneantenna and LTE idle mode operations, as indicated on the left-hand sideof the third row of the table of FIG. 6. Device 10 may be configured tohandle this scenario by placing switch configuring switch 120 to coupleport P6 to port P5 to route received signals from a first antenna topath 1X RX and to route transmitted 1X signals from path 1X TX to thefirst antenna, by configuring switch 124 to couple port P9 to port P7 toroute received signals from a second antenna to path LTE RX2, and byconfiguring switch 144 to couple port P1 to port P3, so that receivers65 and 61 operate at frequencies f2 and f1, respectively. When in the 1Xnon-receive-diversity mode (one antenna), one of the antennas,transmitter 59, one of the receivers in device 10, and basebandprocessor 58 are being used to handle 1X traffic, so there areinsufficient resources available to handle the simultaneous transmissionand reception of LTE traffic (i.e., LTE active mode operations cannot besupported), as indicated by the entry on the right-hand side of thethird row of the table of FIG. 6.

FIG. 11 is a timing diagram showing the operation of device 10 whentransitioning from an LTE active mode to an LTE idle mode andtransitioning from a 1X idle mode to 1X active mode. Initially, device10 is operating in an LTE active and 1X idle state. LTE traffic may behandled using one antenna to transmit LTE data and two antennas (receivediversity) to receive LTE data. Periodically, device 10 may use of oneof the two antennas (e.g., the antenna associated with receiver RX2) tomonitor the 1X paging channel for incoming 1X pages (see, e.g., the 1Xwake interval starting at time TT in the FIG. 11 example). Severaltransmission time intervals before time TT, device 10 may send a rankindicator of 1 (or other channel quality indicator) to the network todirect the network to reduce the transmission of data (i.e., to transmitdata using only one LTE data stream), thereby minimizing disruption toLTE operations during the temporary use of the RX2 receiver andassociated antenna to monitor 1X pages.

When device 10 receives an incoming 1X page, device 10 may transition to1X active mode, as shown in FIG. 11. Because signal quality issufficient (in this example), only a single antenna need be used forhandling 1X data reception activities. Accordingly, the remainingantenna can be used to handle LTE idle mode operations (monitoring theLTE paging channel for incoming pages).

As shown in the fourth row of the table of FIG. 6, LTE operations willbe interrupted when operating in a 1X active mode in environments inwhich the signal strength is insufficient to support operation with onlya single antenna. When operating in a 1X receive diversity (two antenna)active mode, switching circuitry 120 may be configured so that port P6is coupled to port P5 (so that received antenna signals from a first ofthe two antennas are routed to path 1X RX1), switching circuitry 124 maybe configured so that port P9 is coupled to port P8 (so that receivedantenna signals from a second of the two antennas are routed to path 1XRX2), and switching circuitry 144 may be configured so that port P2 iscoupled to port P3 (i.e., so that receivers 61 and 65 operate at thesame frequency). Transmitted 1X signals may be handled using path 1X TX.The use of both antennas to support 1X data reception active modeoperations and the use of one of the antennas to support 1X datatransmission operations will interrupt LTE operations regardless ofwhether it is desired to operate in an LTE idle mode (the left-hand sideof the fourth row of the FIG. 6 table) or in LTE active mode (theright-hand side of the fourth row of the FIG. 6 table).

FIG. 12 is a timing diagram illustrating how the use of both antennas indevice to support 1X active mode operations may interrupt LTE activity.Initially, (e.g., at times before time TW1), both antennas may be usedfor LTE operations (e.g., LTE active mode operations or LTE idle modeoperations). Periodically (e.g., at times such as time TW1 and time TW2in the FIG. 12 example), one of the antennas (e.g., the antenna coupledto receiver RX2) may be used to monitor the 1X paging channel.

To minimize disruption to LTE operations, device 10 may send a rankindicator of 1 or other such channel quality indicator to the networkseveral transmission time intervals before switching use of one of theantennas from LTE activities to 1X page monitoring (i.e., severaltransmission time intervals before 1X page monitoring times such astimes TW1 and TW2). In response, the network can reduce LTE datatransmissions (e.g., by reducing transmissions from two active LTE datastreams to one LTE data stream or taking other suitable action), therebyminimizing disruption to LTE operations.

In the FIG. 12 example, an incoming 1X page is detected at time TW3. Asa result, device 10 enters 1X active mode at time TW3 and uses bothantennas (i.e., the antenna coupled to receiver RX1 and the antennacoupled to receiver RX2) in handling a 1X call. Both antennas are beingused to handle 1X activities, so LTE operations (active mode or idlemode) are interrupted.

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention.

1. A method for communicating with a wireless network using anelectronic device that supports communication using a first radio accesstechnology and a second radio access technology, comprising: during atleast one page monitoring period, using a first of two antennas in theelectronic device to monitor a paging channel associated with the firstradio access technology while simultaneously using a second of the twoantennas to convey wireless data traffic associated with the secondradio access technology; and in response to completion of the pagemonitoring period without detection of an incoming page on the pagingchannel by the electronic device, using both the first and secondantennas to convey wireless data traffic associated with the secondradio access technology.
 2. The method defined in claim 1 wherein thefirst radio access technology comprises a Code Division Multiple Accessradio access technology and wherein the second radio access technologycomprise a Long Term Evolution radio access technology.
 3. The methoddefined in claim 2 wherein the first and second antennas are located atopposing ends of the electronic device and wherein using both the firstand second antennas to convey wireless data traffic associated with thesecond radio access technology comprises using the first and secondantennas that are located at opposing ends of the electronic device toreceive Long Term Evolution data traffic.
 4. The method defined in claim2 further comprising: monitoring wireless signal quality with theelectronic device; and determining whether to use the first antennaalone in monitoring the paging channel or whether to use both the firstand second antennas in monitoring the paging channel based at leastpartly on the monitored wireless signal quality.
 5. The method definedin claim 4 wherein monitoring the wireless signal quality comprisesobtaining a received signal strength indicator that is indicative ofchannel quality for the paging channel.
 6. The method defined in claim 5further comprising: comparing the received signal strength indicator toa predetermined threshold; in response to determining that the receivedsignal strength indicator exceeds the predetermined threshold, using thefirst antenna alone to monitor the paging channel during the at leastone page monitoring period; and in response to determining that thereceived signal strength information does not exceed the predeterminedthreshold, using both the first and second antennas to monitor thepaging channel.
 7. The method defined in claim 6 wherein using both thefirst and second antennas to monitor the paging channel comprisestemporarily interrupting reception of Long Term Evolution data with thefirst and second antennas and, while reception of the Long TermEvolution data with the first and second antennas is temporarilyinterrupted, using both the first and second antennas to monitor thepaging channel for Code Division Multiple Access paging signals.
 8. Amethod for communicating with a wireless network using an electronicdevice that supports wireless communication using a first radio accesstechnology and a second radio access technology, comprising: duringoperation of the electronic device, simultaneously using first andsecond antennas in the electronic device to monitor a paging channelassociated with the first radio access technology; and during at least aportion of the operation of the electronic device, at least partiallyinterrupting the monitoring of the paging channel associated with thefirst radio access technology to monitor a paging channel associatedwith the second radio access technology using the first antenna and notthe second antenna.
 9. The method defined in claim 8 further comprising:during at least another portion of the operation of the electronicdevice, interrupting the monitoring of the paging channel associatedwith the first radio access technology to monitor the paging channelassociated with the second radio access technology using both the firstand second antennas.
 10. The method defined in claim 9 wherein the firstradio access technology comprises a Long Term Evolution radio accesstechnology and wherein the second radio access technology comprise aCode Division Multiple Access radio access technology.
 11. The methoddefined in claim 10 further comprising: measuring wireless channelquality using the electronic device; comparing the measured wirelesschannel quality to a predetermined value, wherein at least partiallyinterrupting the monitoring of the paging channel associated with thefirst radio access technology to monitor the paging channel associatedwith the second radio access technology using the first antenna and notthe second antenna comprises at least partially interrupting themonitoring of the paging channel associated with the first radio accesstechnology in response to determining that the wireless channel qualityexceeds the predetermined value; and in response to determining that thewireless channel quality does not exceed the predetermined value, usingboth the first and second antennas to monitor the paging channelassociated with the second radio access technology.
 12. The methoddefined in claim 11 wherein measuring the wireless channel qualitycomprises gathering received signal strength indicator informationassociated with a wireless channel in the wireless network.
 13. Themethod defined in claim 8 wherein the electronic device comprisesradio-frequency transceiver circuitry and control circuitry thatcontrols the radio-frequency transceiver circuitry and wherein theradio-frequency transceiver circuitry includes first and secondreceivers with respective first and second local oscillators, the methodfurther comprising: adjusting the radio-frequency transceiver circuitryso that the first and second local oscillators produce outputs at acommon frequency when simultaneously using first and second antennas inthe electronic device to monitoring the paging channel associated withthe first radio access technology; and adjusting the radio-frequencytransceiver circuitry so that the first and second local oscillatorsproduce outputs at different frequencies when monitoring the pagingchannel associated with the second radio access technology using thefirst antenna and not the second antenna.
 14. The method defined inclaim 13 further comprising: while the radio-frequency transceivercircuitry is adjusted so that the first and second local oscillatorsproduce outputs at different frequencies, using the first receiver tomonitor paging signals associated with the first radio access technologywhile simultaneously using the second receiver to monitor paging signalsassociated with the second radio access technology.
 15. A method ofsupporting use of first and second radio access technologies in awireless electronic device having first and second antennas and havingradio-frequency transceiver circuitry that transmits and receiveswireless signals using the first and second antennas, comprising: in afirst mode of operation, using the first antenna to monitor a pagingchannel associated with the first radio access technology whilesimultaneously using the second antenna to monitor a paging channelassociated with the second radio access technology; and in a second modeof operation, actively transmitting and receiving data traffic throughthe first antenna using the first radio access technology whilesimultaneously using the second antenna to monitor the paging channelassociated with the second radio access technology.
 16. The methoddefined in claim 15 wherein the first radio access technology comprisesa Long Term Evolution radio access technology and wherein the secondradio access technology comprise a Code Division Multiple Access radioaccess technology.
 17. The method defined in claim 16 wherein thewireless electronic device has a housing, wherein the first and secondantennas are located at opposing ends of the housing, wherein theelectronic device has switching circuitry coupled between the first andsecond antennas and the radio-frequency transceiver circuitry, andwherein the radio-frequency transceiver circuitry further comprisesfirst and second receivers, the method further comprising: operating thewireless electronic device in a first configuration in which theswitching circuitry routes signals from the first antenna to the firstreceiver and routes signals from the second antenna to the secondreceiver; and operating the wireless electronic device in a secondconfiguration in which the switching circuitry routes signals form thefirst antenna to the second receiver and routes signals from the secondantenna to the first receiver.
 18. The method defined in claim 16further comprising: in a third mode of operation, actively transmittingand receiving data traffic through the second antenna using the secondradio access technology while simultaneously using the first antenna tomonitor the paging channel associated with the first radio accesstechnology.
 19. The method defined in claim 18 further comprising: in afourth mode of operation, simultaneously using the first and secondantennas for receiving data traffic associated with the first radioaccess technology.
 20. The method defined in claim 19 furthercomprising: in preparation for temporarily switching from using both thefirst and second antennas for receiving data traffic associated with thefirst radio access technology during the fourth mode of operation tousing the first antenna for receiving data traffic associated with thefirst radio access technology while using the second antenna to monitora paging channel associated with the first radio access technology,transmitting a channel quality indicator to a wireless network from thewireless electronic device to direct the wireless network to reducetransmission of data to the wireless electronic device that isassociated with the first radio access technology.